Carbon dioxide CO2 is a chemical compound of carbon and oxygen. Carbon dioxide is a colorless and odorless gas. It is a natural component of air with low concentration and is produced in living beings in cellular respiration, but also during the combustion of carbonaceous substances under sufficient presence of oxygen. Since the beginning of industrialization, the CO2 fraction in the atmosphere has been rising considerably. The main cause for this rise are the (so-called anthropogenic) CO2 emissions produced by humans. The carbon dioxide in the atmosphere absorbs a part of the thermal radiation. This property makes carbon dioxide a so-called greenhouse gas (GHG) and a contributor to the global greenhouse effect.
For this and also other reasons, research and development is carried out in a large number of directions in order to find a way to reduce anthropogenic CO2 emissions. There is strong need for reducing the CO2 emissions, especially in connection with power generation which frequently occurs by incinerating fossil fuels such as coal, oil or gas, but also in connection with other combustion processes such as the incineration of waste. More than 20 billion tons of CO2 are emitted into the atmosphere by such processes per year.
It is seen as a problem that CO2 is produced in the combustion of fossil fuels. Furthermore, finite fossil resources are irrevocably consumed. Mobility in particular leads to larger emissions. That is why research is conducted in a large number of directions in order to reduce the consumption of vehicles or to develop vehicles which are driven completely by regenerative forms of energy.
It is known that the intake air or the fuel-air mixture can be cooled prior to the compression in the intake passage of an internal combustion engine. This leads to an increase in the density of the gas and therefore to an increase in the mass flow through the machine and to the possibility to combust more fuel in the increased air mass, and therefore to an increase in the specific power.
The working process and therefore also the combustion in the combustion chamber of an internal combustion engine commences at a lower temperature. In the case of a predetermined (due to the thermal loading) combustion end temperature (especially in the case of gas turbines due to blade strength), more heat can also be supplied at the start of combustion at lower temperature, which again leads to an increase in the specific power.
It is the state of the art in nearly all modern diesel engines and in many gasoline engines to provide pre-compression of the combustion air or the fuel-air mixture before the combustion chamber with a special compressor (which is also known as a supercharger or compressor) for the reasons as mentioned above. A radial flow compressor is conventionally used for this purpose, which is driven by a radial exhaust-gas turbine (also known as exhaust-gas turbocharger). The radial flow compressor and the radial exhaust-gas turbine are arranged on a common shaft. The gas (or the charge air respectively) will be heated in a polytropic manner as a result of this compression and will be cooled back according to the state of the art by a heat exchanger (also known as an intermediate cooler or intercooler) which is cooled by external air for example in order to increase the power and efficiency of the engine.
The higher specific power of the machine, in combination with losses that remain the same otherwise, additionally leads to an increase in the efficiency, which will be utilized in combustion engines for example by reducing the size of the machine (downsizing).
The intermediate cooler causes additional constructional effort with respective costs and need for space, and also losses concerning power and efficiency due to its flow resistance (pressure losses).
It is also known that by injecting water or a water-alcohol mixture the intake air or the fuel-air mixture of an engine can be cooled, which occurs both before the compression in the intake passage and also after the pre-compression instead of the intermediate cooler, or even after the intermediate cooler. By injecting such a fluid into the intake air or the fuel-air mixture, it is possible to achieve gains in power and efficiency without pressure losses. This is caused by the fact that the water or the water-alcohol mixture will evaporate and will cool the intake air or the fuel-air mixture according to its evaporation heat.
If this fluid is combustible, which occurs in a water-alcohol mixture, it takes part in the subsequent combustion process in the internal combustion engine under delivery of additional mechanical power.
Different effects can be achieved depending on the configuration of the respective units of such an internal combustion engine and depending on the use of water or water-alcohol mixtures. As a result, the total power and the inner cooling of the internal combustion engine can be increased. This allows downsizing of the internal combustion engine for example, which can contribute to the reduction in the losses and also to a reduction in the emissions.
If alcohol is used, then such alcohol will combust together with the fuel (primary fuel) in the internal combustion engine. If the alcohol were obtained from fossil raw materials, the combustion of the alcohol would lead to additional CO2 emissions however.
It is therefore examined whether or not and the extent to which alcohol can be produced from biogenic resources and can be used in vehicle engines. The use of CO2-neutral alcohol would reduce the CO2 emissions of the vehicle engine which have an effect on the climate. The main focus in this application is on methanol, ethanol and butanol. It has regretfully been noticed that the production of CO2-neutral alcohol entails numerous other disadvantages. The production of these alcohols is frequently in direct competition with food production, or the costs for the CO2-neutral alcohol are considerably higher than the costs of fossil fuels.
Other alternative alcohol-based fuels are often more expensive than the fossil fuels. This is partly caused by the fact that all costs including the environmental costs are included in the production of CO2-neutral alcohol, whereas fossil fuels are currently still offered without the actual consideration of the so-called external costs.
Methanol is an especially advantageous alcohol because it is the simplest alcohol that is available. Methanol is mostly produced until now from fossil raw materials such as natural gas for example. Numerous methods and reactors for the production of methanol are known. Respective exemplary patent applications and patents are mentioned below:                EP 0 790 226 B1;        WO 2010/037441 A1;        EP 4 483 919 A2.        
For the initially mentioned applications there is a demand for the provision of an alcohol-water mixture, which on the one hand is suitable as a cooling fluid and on the other hand is CO2-neutral and cheap in production. Moreover, the alcohol shall not be in competition with food production.